Most commercially available tampon applicators for introducing catamenial tampons intravaginally consist of a pair of telescoping tubes. See, for example, U.S. Pat. 3,696,812. The outer tube is designed to store a tampon at one end. The inner or ejector tube is slightly smaller in diameter and is slidably positioned behind the tampon carried in the outer tube. In use, the tampon is ejected from the applicator by pushing the inner tube into the outer tube to expel the tampon.
Several drawbacks are associated with such applicators for certain uses. For example, such tampon applicators are substantially longer than the tampons. First, the outer tube must be of length sufficient to assure proper depth of insertion. Next, when the tampon and outer tube are assembled with the ejector tube, a major portion of the latter tube necessarily extends out from the end of the outer tube. This results in the over-all length of the packaged ready-for-use tampon applicator being approximately two and one-half times the length of the tampon. As a result of such a relatively large size, the bulk and cost of the packaging for such applicators are increased.
Women commonly carry such packaged tampons (with applicators) in their purses. Because of the length of such applicators, they occupy a relatively large amount of space in the purse. It is therefore also desirable to produce a tampon applicator of smaller size which is less obtrusive. This is a particular problem for younger women who often prefer not to carry purses and with today's fashions often must use pockets in relatively tight-fitting clothes.
Another type of tampon applicator has been proposed to solve the foregoing problems by telescoping the ejector tube completely into the outer tube while storing the tampon in the distal end of the ejector tube. This also shortens the tampon and applicator assembly by the length of a tampon. Operatively, the ejector tube (often referred to as the pusher tube) is "cocked" by being withdrawn proximally out most of the way from its stored position in the outer tube (leaving behind the tampon) until the distal end of the ejector tube is positioned to engage the proximal end of the stored tampon. Each patentee discloses a different way of securing the stored tampon in the distal end of the outer tube to prevent proximal displacement of the tampon while the ejector tube is withdrawn therefrom. See U.S. Pat. Nos. 2,832,342; 3,090,385; 3,101,713; 4,276,881; 4,286,595; and 4,479,791; and British Patent No. 2,033,754.
Apparently, none of the foregoing types of applicators has ever been commercially successful.
Applicators of the conventional telescoping tube type typically include a restraining means to prevent disassembly. See, for example, ribs 20 on one cardboard tube interacting with grooves 18 on the other in U.S. Pat. No. 3,696,812, and similarly see interference ribs 32 and 38 respectively, on opposing plastic tubes in U.S. Pat. No. 3,148,680.
Interlocking restraining means became more important in preventing disassembly in the compact applicator designs, because the added cocking step needs to be controlled to prevent disassembly. These earlier designs also tend to be inadequate, particularly for the compact applicators, because of often being subject to wobble in the fully cocked position. The tendency to wobble is also more likely in molded plastic applicators, which because of manufacturing requirements, are made from tubes which are slightly tapered.
Also, in a compact applicator, the diameters of inner and outer tubes must be more nearly the same, than in the type shown in U.S. Pat. No. 3,148,680, to make room for storing the tampon within the inner tube without the outer tube being too bulky. Thus, interference ribs 32 and 38 cannot be as large in a compact applicator and are thus less effective. This could be somewhat compensated for by making the tubes from a stiff plastic, but this is not functionally nor commercially acceptable. Too stiff a plastic would be too brittle and also would result in an uncomfortable and even injurious applicator (scratching and pinching delicate tissue). Typically the stiffness, measured as the flexural modulus (ASTM D790 procedure), in a tampon applicator should not exceed 90,000 psi. Thus, a compact applicator made from acceptably soft plastic with reasonably small interference ribs normally would not have an effective restraining means for adequately interlocking the telescoping tubes to prevent disassembly in normal use.